Oil-flotation process and apparatus



D. F. HALEY.

OIL FLOTAIION PROCESS AND APPARATUS.

APPLICATION FILED JUNE 4. 1915.

1,357,556, I Patented Nov. 2, 1920.

' v 2 SHEETS-SHEET I- ATTORNEYS D. F. HALEY.

.OIL FLOTATION PROCESS AND APPARATUS.

APPLICATION FILED JUNE 4. l9l5.

Patented Nov. 2, 1920.

2 SHEETS-SHEET 2- INVENTOR ,4 ITURNEYS UNITED STATES PATENT 0FFECE..

DENNIS FREDERICK HALEY, OF WALLACE, IDAHO, AS SIGNOR TO METALLURGICAL COMPANY OF AMERICA, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

OIL-FLOTATION PROCESS AND APPARATUS.

Specification of Letters Patent.

Patented Nov. 2, 1920 To (11100710122 it may concern:

Be it known that I, DENNIS FREDERICK HALEY, a citizen of the United States, resid ing in \Vallace, county of Shoshone, and State of Idaho, have invented certain new and useful Improvements in Oil-Flotation Processes and Apparatus; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the separation of metallic particles, and particularly metallic sulfids, by a froth flotation process and apparatus, from the gangue with which they are associated; and it comprises, as a process. a froth flotation process of concentrating ores and of separating metallic particles, particularly metallic sulfids, from their associated gangue by intimately mixing the ore pulp with oil, or other appropriate frothing or selecting agent, and advantageously also with air, in a centrifugal pump, and discharging such intimate mixture in the form of a stream or jet at a high velocity downwardly through an atmosphere of gas, such as atmospheric air into a body of water or aqueous liquid, and thereby aerating the pulp and forming a froth, the froth being suitably separated and removed, the pulp being again treated, thereafter if desired to effect further concentration until the desired separation has beeneifected and it comprises, as an apparatus,'a flotation box, advantageously having therein a receptacle of relatively small size arranged to overflow into said box, and an injector or therefrom; it further comprises such an i a frothing agent or with a frothingfagent and air, and to discharge the same through said apparatus made up of a series of such flotation boxes with such injectors, provided with means for removing the froth therefrom, advantageously without overflow of the liquid therewith, and centrifugal pumps arranged to intimately mix the'pulp with injectors, together with means for feeding the pulp and frothing agent to the first of said pumps and means for feeding the tailings from the bottom of each box and the 'suspended particles from each box beneath the froth together with a frothing agent to the pump which supplies the next flotation box; and it also comprises certain further novel elements and combinations and arrangements of parts of the apparatus, all as more fully hereinafter set forth and as claimed.

In froth flotation processes of concentrating sulfid ores the ore is mixed with a small amount of oil or other appropriate frothing or selecting agent and aerated, the selective affinity of the sulfid particles for the frothing agent and air causing the metallic particles to adhere to the air bubbles and to rise to the surface in the form of a froth, while the gangue, because of its relatively greater preference for water, settles out or remains in the aqueous pulp.

The present invention relates to an apparatus for effecting such separation, which is simple and inexpensive in construction. and operation; and to a process for effecting such separation in a particularly advantageous manner.

In carrying out the process of the present invention the ore, in the form of a pulp of suitable consistency is mixed with a small amount of oil or other appropriate frothing or selecting agent, and advantageously also with air, in a' centrifugal pump, and the resulting mixture is discharged with a relatively high velocity downwardly through an atmosphere of gas, such as air, into a body of liquid into which it splashes and is thereby aerated, and a froth produced. The relative proportions of solids, liquids, and air should be such as to cause the metal partioles to adhere to the air bubbles and to float upon the surface of the liquid in the form of a froth. The selectivity of the metal particles for the frothing or selecting agent and y for the air bubbles can on some ores be promoted by the addition of a small amountof acid, in a manner which will be readily uncles and to form with the metallic particles the desired froth; while the gangue, which is not .wet by the-fiothing or selecting agent, but-which has aipreferencefor water,

remains mixed with the water and tends to separate out. The amount of frothing agent can be varied with the particular ore treated, and may in practice vary-from a fraction of a per cent. to a few per cent. The amount of frothing agent should not be too large to prevent the desired air bubble adhesion. The relative amounts of frothing agent, water and air should also advan-.

form' of apparatus embodying the invention and in which the process of the invention can be practised; but it is intended and understood that the invention will be illus trated by, but is not limited to, the specific embodiments so illustrated and described; although suchembodiments are particularly advantageous and represent what I now believe'to be the best form of apparatus for practisingthe invention.

In the accompanying drawings,

Figure 1 is a plan of a portion of a flotation plant embodying the invention.

Fig. 2 isa plan of one of the intermediate 1 elements of this plant.

Fig. 3 is an end elevation, with parts in section, of one of said elements.

Fig. 4 is a side elevation, with parts in section, of such element.

Fig. 5 is a detail section taken on line 5-5 of Fig. 2, and

Fig. 6 is a detail section taken on line 6-6 of Fig. 2.

In the apparatus illustrated a collecting or settling tank is indicated at 1 supplied by suitable means (not shown). From this tank the ore pulp is led by the outlet trough 2 provided with suitable valve means (not shown) to the first feed box 3 where it is mixed with a suitable amount of an appro priate frothing or selecting agent by means of the pipe 4 leading from a suitable and regulable supply. From the feed box 3 the pulp mixed with frothing agent is fed to the centrifugal pump 5 driven by any suitable means suchas a belt 6 and pulley 7. This pump draws in the pulp and the frothing agent and advantageously also more or less air, and intimately mixes the pulp with the frothing agent and the air, and discharges the resulting mixture upwardly through the pipe 8 which terminates in a downwardly opening injector or discharge nozzle 9. This system or process. the pulp overflow from the cylinder 10 into to overflow into the box 11. The dischargenozzle 9 is arranged a suitabledistance above the cylinder 10 to permit the mixture discharged downwardly to be somewhat spread out and to entrain more or less air with it, so that the mixture upon entering the cylinder is aerated and airi s beaten into the pulp. This action may properly be called a splashing, and accordingly I call the process of the present invention a splash The froth formed and the flotation'box 11 Where the froth floats upon the surface of the liquid therein. This froth is advantageously removed without overflow over the end of box 11. For this purpose there is provided an outlet 12 dischargins into an overflow box 13 provided with an outletpipe 14 leading to the concentrate launder 15. The outlet 12 has a discharge gate 16 for varying the level and for preventing overflow of the liquid with the froth. In order to remove the froth without overflow of the liquid, scraper blades 17 are provided carried by arms 18 and arranged to rotate slowly with the shaft 19, the arrangement being such that as the scraper blades slowly rotate the froth will be scraped from the surface pf the liquid, the scrapers thus having a skimming action and scraping the froth into the overflow box 13. From the bottom of the flotation box avalve-controlled outlet 20 is provided discharging into the feed box 21 from which the tailings are fed by the launder 28 to the next pump. Arranged at one side of the flotation box is an overflow opening 22, and arranged in front. of this opening is a baffle 23 extending below the surface of the liquid so that overflow of the froth is prevented, the liquid. below the froth escaping between the baffle 23 and the adjustable gate 25 by means of which the overflow level can be varied. The baffle 23 is spaced apart from the side of the box by the spacing members 24. The overflowis received in an overflow box 26 having a pipe outlet 27 leading to the launder 28 from which the overflow is conveyed, together with the tailings from the outlet 20, to the receiving tank inlet or trough 29 of the feed box 3 of the next element of the apparatus. WVith the overflow 22 arranged slightly below the opening 12 by means of which the froth is removed, the liquid level within the flotation box is kept below the froth outlet so prevented. It will be understood that by means of the adjustable gates 16 and 25,

the amount of pulp to be handled.

the relative levels of the openings 12 and 22 can be somewhat. varied. The valve-controlled outlet 20 is open sufficiently to allow the material settled in the box to flow out but open only to such an extent that water is at the same time flowing out of the adjustable overflow. From the feed box 3 of the next element of the apparatus, the pulp, now consisting of the tailings and overflow from the preceding flotation box, is mixed with a further amount of oil 'or other appropriate frothing agent and fed into another centrifugal pump, together with entrained air, from which pump the mixture is discharged into another flotation box in substantially the manner already described. It will be understood that in practice several flotation .boxes are arranged in series, and that the number of such boxes can be varied as desired. With certain ores T have found a series of eight boxes suflicient to secure the desired concentration and separation of the ore.

In the operation of the apparatus and in the practising of the novel process of the present invention therein, the ore in the form of a suitable pulp is collected in the collecting and settling tank 1. Thus in an ore treating'mill the fine pulp from all over the mill may be fed into this settling tank. This tank can be of any suitable or preferred construction to produce a pulp of the desired consistency. The thickness of the pulp can however be varied and the thickness of this pulp in the process and apparatus of the present invention has relatively less bearing on the successful operation of the process and the recovery of the values from the pulp, than in other floation processes. The thickened pul from this settling tank flows into the feed box at a rate which can be regulated as desired. In this feed box the pulp is mixed with oil or other frothing agent, sufiicient frothing agent, being introduced to enable the sulfid particles to form a froth of the desired consistency when discharged as described, From this feed box the pulp together with the frothing agent is pumped by means. of the centrifugal pump into'the first flotation box. .It will be understood that the size of this pump, as well as its construction, can be varied, depending upon The size of the discharge orifice 9.can also be varied with the amount of pulp to be handied, a diameter pf from to of an inch having been found in practice particularly advantageous. The end of this discharge pipe 9 is in practice arranged about. six

inches above the top of the cylinder 10, this cylinder having in practice a dlameter of about six inches. The pulp is intimately mixed with the oil or other frothing agent by means of the centrifugal pump and this pump is also advantageoi-isly arranged to draw in air also and to intimately mix this air with the frothing agent and with the pulp so that the mixture discharged from the outlet pipe 9 is already partly aerated. The mixture is discharged downwardly with considerable velocity and splashes into the receptacle 10, a large amount of air being entrained therewitlraiul beaten into the pulp with the result that the sulfld particles are intimately associated or coated with the oil' or other frothing agent and are also intimately associated with fine air bubbles. The

sulfid particles are thus entrapped by the oil or other frothing agent and air and into the flotation box. The thorough emulsi fication of the pulp with the frothing agent and air in the pump and the further aeration of the mixture upon its discharge into the liquid in the cylinder 10 results in the formation of a thick froth which collects and floats upon the surface of the liquid in the flotation box. This froth is not allowed to overflow butis scraped off by the scraper in the manner already described and is collected in the launder 15. The scrapers will in practice rotate with a slow speed so that agitation of the liquid is avoided and so that the froth is removed at the desired rate. lVith the outlet 20 open sufficiently to allow the material which has settled in the box to flow out but open only sufficiently to permit a part of the inflowing liquid to flow out this way, a continual overflow will take place through the side overflow 12, overflow of the froth being prevented by the baflie 23, in the manner already described. W'ith this arrangement for a continual overflow from the top of the flotation box'withlayers of the liquid below the froth are removed and collected for further treatment. Both the tailings and the overflow pass into the launder and feed box to the next pump. Where the operation is repeated. More or less of, the concentrate will be removed in each box and a sufficient number of boxes can be placed in series'to effect the desired grade, this concentrate can be further treating series can be returned to the settling tank 1 and subjected to the process already described. It will be'understood that the flo tation boxes can be made larger or smaller in size, and that the other parts of the apparatus can similarly be varied in size, de-

pending upon the tonnage which it is desired to handle. The apparatus above described is particularly advantageous where the ores contain considerable amounts of colloidal matter, most of such colloids flowing off from beneath the trough-through the water from the side overflow.

In carrying out the process different oils or other appropriate frothing or selecting agents can be used, as will be readily understood, and the relative amounts of frothing agent can also be varied from a fraction of a per cent. to a few per cent., depending upon the ore bein treated. In the treatment of zinc sulfic l and lead sulfid ores I have found pine oil and creosote to be particularly advantageous. It will also be understood that on some ores the pulp-can beslightly acidified to promote or increase the selective attraction. of the frothing agent for the sulfids and of the gangue for the water,

the amount of acid being sufficient for this purpose without being sufficient to affect the metallic constituents. Heat may also be used to promote the fluidity of the oil although inpractice heating may not be necessary or desirable. The amount of frothing agent, and the other conditions of the process such as the relative amounts of water and solids, and the presence or absence of small amounts of acid or of acid salts, is advantageously such that coagulation of the sulfid particles will take place during the process. While the apparatus illustrated and described has been found particularly advantageous in carrying out the novel process of the present invention, yet it will be under stood that variations and modifications can be made therein, and in the process as described without departing from its and scope.

I claim: U

1. The process of concentrating ores by flotation" which comprises, intimately mixspirit ,ing an orepulp with a frothing agent and with air, discharging the resulting mixture in the form of a stream through an atmosphere of gas ,into a body of liquid and thereby forming a froth, and causing the froth thus formed to float by overflow upon the surface of a body of liquid, whereby the froth is not permitted to get below the surface of the liquid upon which it is floated and is not permitted to become intermixed with the colloids of said body of liquid.

2. The herein described continuous process of concentrating ores, including continuously fluidizing the ore containing mineral to be separated, continuously injecting a liquid jet through an atmosphere of gas directly and forcibly into a body of the fluidized ore to form a froth and continuously withdrawing the fluidized ore from the body and separating the froth from the remaining fluidized material.

3. The herein described process of con-- centrating ores, which embodies the formation of a froth by projecting a liquid through an atmosphere of gas into direct and forcible contact with a body of the ore in fluidized state.

4. The herein described process of concentrating ores, which'embodies the formation of a froth by projecting a liquid through an atmosphere of gas into direct and forcible contact with a restricted and comparatively small volume of the ore in fluidized state.

5. The herein described process of concentrating ores, which embodles the projection of the ore, a liquidand a selective agent through an atmosphere of gas into direct and forcible contact with a body of the ore in fluidized state.

6. The herein described process of concentrating ores, which embodies the projection of the ore, a liquid and a selective agent throughan atmosphere of gas into. direct and forcible contact with. a restricted and comparatively small volume of the ore in fluidized state.

'7. The herein described process of concentrating ores which embodies. the projection of the ore, a liquid and a selective agent through an atmosphere of gas into direct and forcible contact with a restricted and comparatively. small volume of the ore in fluidized state to draw gas into the fluidized ore and agitate it and form a froth, and the separation of the froth from the 'remainder of the fluidized material by flotation over a larger body of the fluidized material itself.

8. A froth flotation apparatus comprising a flotation box having therein a receptacle holding a relatively small body of liquid and arranged to overflow into said box, and an injector arranged above the liquid level in said box to discharge a jet ofpulp mixed with an appropriate frothing agent downwardly into the liquid in said receptacle and to aerate saidpulp and form a froth' therefrom.

9. A froth flotation apparatus compris ing a centrifugal pump adapted to intimately mix pulp, frothmg agent and air, means for feeding pulp, frothing agent and air to said pump, a flotation box having therein a receptacle holding a relatively small body ofvliquid and arranged to overflow into said box, and an injector connected with the discharge of said pump and arranged above the liquid level in said box to discharge the mixture of pulp and frothingagent from said-pump downwardly into the liquid in said flotatlon rece tacle, and

to aerate said pulp and form a roth there: from.

10. The process ofconcentrating ores by flotation which, comprises, discharging a stream of ore pulp intimately: mixed with a frothing agent at high velocity through an atmosphere of gas mto a body' of hquid, and thereby aerating the pulp and forming a froth.

-11. The process of concentrating ores by flotation which comprises, discharging a stream of ore pulp intimately mixed with a frothing agent at high velocity into a relatively small confined body of liquid arranged -to overflow into a conslderably larger body of similar liquid, and thereby aeratin the pulp and forming a froth.

12. heprocess of concentrating ores by flotation which comprises, discharging a stream of ore'pulp intimate y mixed with a frothing agent at high velocity through an atmosphere of gas into a body ofliquid, and thereby aerating the pulp and forming a froth, and removin the froth from the surface of the liqui on which it floats without overflow of the liquid therewith.

18. The process of concentrating ores by flotation which comprises, discharging a stream of ore pulp intimately mixed with a frothing agent at high velocity through an atmosphere of gas into a relatively small confined body of liquid arranged to overflow level in said receptacle and arrange into a considerablylarger bod of similar flotation box, a receptacle of considerably smaller capacity than said box arranged within the box to permit the overflow of liquid from the receptacle into the box, and an injector positioned with its discharge outlet above the normal operating liquid to dis-v charge astream of ore pulp mixed with a frothing agent downwardly through an atmosphere of gas into the liquid in said receptacle and to thereby aerate said pulp and form a froth.

15. A flotation apparatus comprising a flotation box having therein a receptacle holding a relatively small body of liquid and arranged to overflow into said box, an injector arranged to discharge a stream of ore pulp mixed with an appropriate froth- .ing agent' downwardly through an atmosphere of gas into the liquid in said ,receptacle and to aerate said pulp and form a froth therewith, a scraper arranged to scrape the froth from the liquid on which it floats in said box without overflow of the liquid therewith, an overflow arranged to permit overflow of the liquid from said DENNIS FREDERICK HALEY.

Witnesses:

. SYLVESTER T. ALLEN, 'H. H. BARNES.

. box without overflow of the froth therewith, 

